Canada-wide gas boiler information · On-site service in Greater Vancouver, BC
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Comparison
Verdict in brief
The Lochinvar Knight KHB155 and Lochinvar Knight KHB199 are both condensing boilers in the Lochinvar Knight Floor Mount (KHB) line. Published ratings: Lochinvar Knight KHB155 at 15.5–155 MBH input, 144 MBH DOE heating capacity and 95% AFUE; Lochinvar Knight KHB199 at 19.9–199 MBH input, 183 MBH DOE heating capacity and 95% AFUE. Lochinvar Knight KHB199 lists 44 MBH more input than Lochinvar Knight KHB155 (199 MBH against 155 MBH). Both list the same published AFUE of 95%.
Published manufacturer figures. Input and output are kept separate; blanks mean the manufacturer did not publish that value.
| Specification | Lochinvar Knight KHB155 | Lochinvar Knight KHB199 |
|---|---|---|
| Heating input, minimum | 15.5 MBH | 19.9 MBH |
| Heating input, maximum | 155 MBH | 199 MBH |
| Efficiency (AFUE) | 95 % | 95 % |
| Domestic hot water | Heating-only boiler | Heating-only boiler |
| Water content | 3.2 gal | 5.2 gal |
| Venting | Category IV sealed combustion; PVC, CPVC, polypropylene or stainless steel | Category IV sealed combustion; PVC, CPVC, polypropylene or stainless steel |
| Max. equivalent vent/air length, 3" | 100 ft | 100 ft |
| Space-heating water connections | 1" | 1-1/4" |
| Gas connection | 1/2" | 1/2" |
| DOE heating capacity | 144 MBH | 183 MBH |
| AHRI net water rating | 125 MBH | 159 MBH |
Published ratings: the Lochinvar Knight KHB155 is rated 15.5–155 MBH input, 144 MBH DOE heating capacity and 95% AFUE; the Lochinvar Knight KHB199 is rated 19.9–199 MBH input, 183 MBH DOE heating capacity and 95% AFUE. Lochinvar Knight KHB199 lists 44 MBH more input than Lochinvar Knight KHB155 (199 MBH against 155 MBH). Both list the same published AFUE of 95%.
The boiler water content differs: the Lochinvar Knight KHB155 lists 3.2 gal, while the Lochinvar Knight KHB199 lists 5.2 gal. The water connections differs: the Lochinvar Knight KHB155 lists 1", while the Lochinvar Knight KHB199 lists 1-1/4".
Both records print the same AFUE (95%), domestic-hot-water arrangement (Heating-only boiler), venting (Category IV sealed combustion; PVC, CPVC, polypropylene or stainless steel) and max. equivalent vent/air length, 3" (100 ft), per the cited sources.
Lochinvar
The Knight KHB155 is the 155 MBH floor-standing Knight: 15.5 to 155 MBH input at 95% AFUE with 144 MBH DOE capacity, vented in 3" pipe to 100 equivalent feet.
Lochinvar
The Knight KHB199 is the 199 MBH floor-standing Knight: 19.9 to 199 MBH input at 95% AFUE with 183 MBH DOE capacity, 1-1/4" connections and 3" venting.
The Lochinvar Knight KHB199 lists 199 MBH, against 155 MBH on the Lochinvar Knight KHB155, per the cited documentation.
Both list the same AFUE of 95%.
A consultation includes a heat-loss review so the size is right the first time.
On-site service in Greater Vancouver, BC. ROMA lists “Open 7 days” on its site; call to confirm same-day availability.
Sources and verification
Facts checked September 9, 2026. Last updated September 9, 2026. Technical reviewer: not yet assigned.